J.D. Gibbs, co-chairman of Joe Gibbs Racing, died Friday after a long battle with a degenerative neurological disease. Gibbs was 49.

During Gibbs' longtime association with JGR, he also served on pit crews and drove in 13 NASCAR races from 1997 to 2002, five in the Xfinity Series and eight in the truck series. His best finish was 20th in an Xfinity race at South Boston (Virginia) Speedway in July 1998.

Health issues for Gibbs, the eldest son of Joe Gibbs, first became a concern late in 2014, according to NASCAR.com.

Gibbs' father first addressed the seriousness of his son's health in March 2015, speaking to reporters before a Cup race at Martinsville Speedway. "We’ve been dealing with this for about six months," Joe Gibbs said, "and basically what the doctors say is that they really don’t know.”

In a statement earlier that week, JGR revealed Gibbs had been receiving treatment for “symptoms impacting areas of brain function." The statement said, “Doctors believe the complications he has experienced were triggered by head injuries likely suffered earlier in life, but no specific injury was referenced or identified.” The Washington Post noted at the time that Gibbs had been "active in a number of sports, including auto racing, mountain biking, snowboarding, football and extreme sports." He also played football at William & Mary.

Gibbs, whose personality made him a favorite in the NASCAR community, knew early on his future wasn't as a driver.

“If it was just me, I could be a pretty good racer,” he told The Washington Post in 2004, per NASCAR.com. “But then you put 42 other cars out there and that causes some issues.”

In 2014, Gibbs displayed that same sense of humor, when he said, “My dad, he fired me in a nice way. He gave me an office and said, ‘Hey, you’re now the president, because you’re a horrible driver.’”

The NASCAR community was quick to react on social media to Gibbs' passing.

"If you want to know how to live life the right way and leave a legacy that will last forever, look no further than the example J.D. Gibbs set for all of us," said Steve O'Donnell, NASCAR's chief racing development officer.Brad Keselowski, the 2012 Cup champion, reflected a common sentiment as news spread. He wrote, in part: "I'm so sad. This is awful news."

One driver who was especially close to Gibbs was Denny Hamlin, whose entire NASCAR career has been with Joe Gibbs Racing. "I will always be grateful for what His family did for mine and the opportunity he gave me 14 years ago," said Hamlin, 38, who made his first NASCR start at age 23 in what is now the Xfinity Series for JGR.Funeral arrangements are pending, JGR said. Gibbs is survived by his wife, Melissa, and four sons.